1. Field of the Invention
The present invention relates to an abnormality determining apparatus for a motion control apparatus, the abnormality determining apparatus being applied to a vehicle motion control apparatus provided with a control unit having mounted thereto an actuator for controlling a vehicle motion and a vehicle behavior sensor arranged integral with the control unit and outputting a signal indicating a behavior of the vehicle, and determining whether abnormality occurs or not relating to the motion control apparatus.
2. Description of the Related Art
Conventionally, there has been widely known a vehicle motion control apparatus that controls the vehicle motion (attitude) through the control of the hydraulic braking force of the vehicle. In general, the motion control apparatus is configured to include a control unit (hydraulic unit (HU)) having mounted thereto various actuators (motor, solenoid valve, or the like) for controlling the hydraulic braking force of the vehicle; vehicle behavior sensor (yaw rate sensor, and the like) that outputs a signal indicating the behavior of the vehicle; and an electronic control apparatus (ECU) for controlling the actuators on the basis of the output from the vehicle behavior sensor.
In order to achieve a space saving of the entire motion control apparatus and reduction in production cost, a technique has recently been developed for incorporating the vehicle behavior sensor into an integrated unit composed integrally of the hydraulic unit and ECU (e.g., see following patent reference 1).
[Patent Reference 1]
Japanese Translation of Unexamined Patent Application No. 2004-506572
Vibration is generated on the integrated unit (specifically, hydraulic unit and ECU) due to the operation of the actuators mounted thereto. Therefore, when the vehicle behavior sensor is incorporated into the integrated unit (i.e., when the vehicle behavior sensor is integrally mounted to the hydraulic unit and ECU), the vibration can directly be transmitted to the vehicle behavior sensor.
As a result, the vibration noise can greatly be superimposed on the output from the vehicle behavior sensor, whereby the vehicle motion control may not be executed appropriately. Therefore, the integrated unit (accordingly, hydraulic unit and ECU) is generally fixed to the vehicle body via an elastic structural member made of a bracket, mount, and the like, as disclosed in the above-mentioned reference. With this configuration, the vibration transmitted to the vehicle behavior sensor is damped, whereby the vibration noise superimposed on the output from the vehicle behavior sensor can be reduced.
Meanwhile, in the hydraulic unit, the actuators mounted to the hydraulic unit are generally operated with a predetermined pattern immediately before the start of the engine (accordingly, immediately after the start of the electric power supply to the integrated unit) in order to execute a failure check of the apparatus (specifically, a check for disconnection, short-circuit, or the like, so-called primary check (hereinafter referred to as “PC”)).
The vibration caused by the operation of the actuators is inevitably transmitted to the vehicle behavior sensor even during the time that the actuators are operated with this primary check, resulting in that the vibration noise appears on the output from the vehicle behavior sensor. The present inventor has found a technique for detecting abnormality involved in the motion control apparatus by positively utilizing the vibration noise appearing on the output from the vehicle behavior sensor.